The present invention relates to an improved apparatus and method for treating materials with shock waves, and, more particularly, to a more efficient apparatus and method for achieving shock-induced phase transformations in materials according to which two opposing shock waves generated by a substantially simultaneous detonation of explosive pass coaxially through the material to be shocked from either end of its axial dimension on a converging path to a point of collision. Using a shocking tube and, optionally a driver tube, with an explosive charge detonated according to the invention, it is possible to substantially increase yield per shot, e.g., up to 50% or more, and eliminate the need for elaborate end-plugs.
Current methods for explosively shocking materials employ a shocking tube for containing the material to be shocked. The explosive charge surrounds the shocking tube and typically extends for the length of material to be shocked. Alternatively, the explosive surrounds a driver tube which is placed coaxially around the shocking tube at a predetermined stand-off distance. In either arrangement, the explosive is typically initiated substantially simultaneously at all points in one transverse plane, usually coincident with one end of the length of material to be shocked. Shocking is accomplished as the shock wave generated by detonation of the explosive passes through the material. Shocking tubes of the type currently used require generally elaborate end-plug closures for containing the material during detonation of the explosive which can substantially reduce the volume available for holding the material. Such end-plugs are not only required to retain the sample within the shocking tube, but they are also required to carry off the momentum associated with a high pressure shock wave with a minimum of reflected waves.